Computing and plotting offsets and waypoints in RIC and VNB frames

- Adding new ConvertOffset method for converting a single vector from
one frame to another
- Computing offsets in RIC and VNB frames (linear and nonlinear motion)
- Adding plots of relative trajectories in RIC and VNB frames in
addition to RLP
- Computing waypoints in RIC and VNB frames and adding waypoints to
plots as well